Regeneration patterns of three mediterranean pines and forest changes after a large wildfire in northeastern Spain

Fire has favored pines throughout their natural range in environments subject to continuous disturbances, such as the Mediterranean Basin. However, recovery of pine species after large fires is not always successful. In this study, we analyze the post-fire regeneration pattern of Pinus halepensis, P. nigra and P. sylvestris three years after fire, in an area affected by a large wildfire in 1994. Moreover, we develop a model of succession to predict medium-term changes in forest composition 30 years after fire from the regeneration monitored during the first years after fire. The results show that, although the three pine species regenerate quite well in the absence of fire, their post-fire regeneration is very different: P. halepensis shows high seedling density after fire, but P, nigra and P, sylvestris almost dissapear from burned plots. The model simulations of the future forest composition 30 years after fire indicate that 77-93% of plots dominated by these two pines change after fire to communities dominated by oaks (Quercus ilex, Q. cerrioides). There is also a considerable number (7-16%) of these burned pine plots that change to shrublands. Thus, these observational and modelling results suggest that large fire events, which have increased considerably in the Mediterranean region in the last decades, may decrease the overall distribution of these pine species, especially that of P, nigra and P, sylvestris.